ASVAB Automotive Information Practice Test 418886

Questions 5
Topics Crankshaft, Cylinders, Firing Order, Springs, Wheel Hub

Study Guide

Crankshaft

The crankshaft converts the reciprocating motion of the piston into the rotational motion that's used to power the vehicle and its components.

Cylinders

Cylinders act as a guide for the pistons that translate the heat energy of combustion into the mechanical energy necessary to move a vehicle. Piston rings seal the piston to the cylinder to contain combustion gases and also regulate the oil distribution between the piston and cylinder wall. A cylinder head closes in the top of the cylinder forming the combustion chamber which is sealed by a head gasket (head). The head provides space for air and fuel intake valves, exhaust valves, and mounts for spark plugs and fuel injectors.

Firing Order

The stroke cycle of an engine is governed by the crankshaft which serves to regulate the firing order of the cylinders. All cylinders are not on the same stroke at the same time and correct firing order is important to balance engine operation and minimize vibrations. A common firing order for four-cylinder engines is 1-3-4-2 which indicates that cylinders 1 and 3 fire (power stroke)together and cylinders 4 and 2 fire together.

Springs

Suspension springs are made with wide gap coils of rigid steel cable and both hold the vehicle chassis up off the ground and absorb energy from wheel movement making for a smoother ride.

Wheel Hub

The wheel hub is the mounting point for the wheel and tire assembly. The wheel hub can rotate while being held stable by the steering knuckle which applies the motion of the control arms to the wheels.